/*=====================================================================*
 *                   Copyright (C) 2011 Paul Mineiro                   *
 * All rights reserved.                                                *
 *                                                                     *
 * Redistribution and use in source and binary forms, with             *
 * or without modification, are permitted provided that the            *
 * following conditions are met:                                       *
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 *     * Redistributions of source code must retain the                *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer.                                       *
 *                                                                     *
 *     * Redistributions in binary form must reproduce the             *
 *     above copyright notice, this list of conditions and             *
 *     the following disclaimer in the documentation and/or            *
 *     other materials provided with the distribution.                 *
 *                                                                     *
 *     * Neither the name of Paul Mineiro nor the names                *
 *     of other contributors may be used to endorse or promote         *
 *     products derived from this software without specific            *
 *     prior written permission.                                       *
 *                                                                     *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND              *
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,         *
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES               *
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE             *
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER               *
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 * Contact: Paul Mineiro <paul@mineiro.com>                            *
 *=====================================================================*/

#ifndef __MSTEP_HH__
#define __MSTEP_HH__

#include "newton.hh"
#include "qfunc.hh"

namespace playerpiano
{
  template<typename PRating,
           typename Distribution>
  class MStepFunc
    {
      private:
        const PRating&                  prating;
        const std::vector<float>&       pz;
        const std::vector<Rating>&      ratings;
        const Distribution&             priorlogbeta;
        float                           hq;

      public:
        MStepFunc (const PRating&               _prating,
                   const std::vector<float>&    _pz,
                   const std::vector<Rating>&   _ratings,
                   const Distribution&          _priorlogbeta,
                   float                        _hq)
          : prating (_prating),
            pz (_pz),
            ratings (_ratings),
            priorlogbeta (_priorlogbeta),
            hq (_hq)
          {
          }

        float
        operator() (float       logbeta,
                    float&      dlogbeta,
                    float&      ddlogbeta) const
          {
            return qfunc (prating, logbeta, dlogbeta, ddlogbeta,
                          pz, ratings, priorlogbeta, hq);
          }
    };

  template<typename PRating,
           typename Distribution>
  float
  mstep (const PRating&                 prating,
         float&                         logbeta,
         const std::vector<float>&      pz,
         const std::vector<Rating>&     ratings,
         const Distribution&            priorlogbeta,
         float                          hq,
         unsigned int                   maxeval,
         float                          tol)
    {
      MStepFunc<PRating, Distribution> mstepfunc (prating,
                                                  pz,
                                                  ratings,
                                                  priorlogbeta,
                                                  hq);

      return newton (mstepfunc, logbeta, maxeval, tol);
    }
}


#endif // __MSTEP_HH__
